A deconstructive oxygenation of unstrained primary cycloalkanamines has been developed for the first time using an auto‐oxidative aromatization promoted C(sp3)−C(sp3) bond cleavage strategy. This metal‐free method involves the substitution reaction of cycloalkanamines with hydrazonyl chlorides and subsequent auto‐oxidative annulation to in situ generate pre‐aromatics, followed by N‐radical‐promoted ring‐opening and further oxygenation by 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) and m‐cholorperoxybenzoic acid (mCPBA). Consequently, a series of 1,2,4‐triazole‐containing acyclic carbonyl compounds were efficiently produced. This protocol features a one‐pot operation, mild reaction conditions, high regioselectivity and ring‐opening efficiency, broad substrate scope, and is compatible with alkaloids, osamines, and peptides, as well as steroids.

Brassinosteroids (BRs) are phytohormones that regulate numerous processes including fruit ripening. In this study, persimmon ( Diospyros kaki L.) fruits were treated with 24-epibrassinolide (EBR) or brassinazole (Brz, a BR biosynthesis inhibitor) and then stored at ambient temperature. The results show that endogenous BR contents gradually increased during persimmon fruit ripening. EBR treatment significantly increased both the content of water-soluble pectin and the activities of polygalacturonase, pectate lyase, and endo-1,4-beta-glucanase but significantly reduced the content of acid-soluble pectin and cellulose, resulting in rapid fruit softening. The EBR treatment also promoted ethylene production and respiration rate. In contrast, Brz treatment delayed persimmon fruit ripening. qRT-PCR analysis showed that DkPG1, DkPL1, DkPE2, DkEGase1, DkACO2, DkACS1, and DkACS2 were up-regulated (especially a 38-fold increase in DkEGase1) in the fruit of the EBR-treated group. These results suggest that BRs are involved in persimmon fruit ripening by influencing cell-wall-degrading enzymes and ethylene biosynthesis.

An ovel radical 1,4/5-amino shift from the oxygen center of alkene-tethered diphenyl ketoxime ethers to the carbon center to achieve high value-added fluoroalkyl-containing primary b(g)-amino-ketones is reported. Mechanism studies reveal that the migration is triggered by the alkene addition of fluoroalkyl radical derived from the electron donor-acceptor (EDA) complex of Tognisr eagent II or fluoroalkyl iodides and quinuclidine,a nd involves au nique 5(6)-exo-trig cyclization of the carbon-centered radical onto the N-atom of ketoxime ethers followed by acascade sequence of NÀObond cleavage and dehydrogenation. Notably,besides Tognisreagent II and fluoroalkyl iodides,this protocol is also compatible with other radical precursors to provide various functionalizedprimary aminoketones.

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Background: Histone methylation is considered to play an important role in the occurrence and development of periodontitis. Plant homeodomain finger protein 8 (PHF8), a histone demethylase, has been shown to regulate inflammation and osteogenic differentiation of bone marrow stromal cells (BMSCs). This study aimed to detect the functions of PHF8 and TLR4 in osteogenic differentiation in an inflammatory environment induced by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) Methods: A periodontitis mouse model was established, and the mice were treated with TAK-242. Immunohistochemical staining was used to detect the expression of PHF8 in periodontal tissue. Periodontal ligament cells (PDLCs) were treated with mineralization induction medium supplemented with Pg-LPS and/or TAK-242, and a Cell Counting Kit-8 (CCK-8) assay was used to detect the proliferation of PDLCs. Real-time PCR and western blotting were used to detect the mRNA and protein expression levels, respectively, of PHF8, toll-like receptor 4 (TLR4) and the other osteogenic markers alkaline phosphatase (ALP), osteocalcin (OCN), Special AT-rich sequence-binding protein 2 (Satb2) and Runt-related transcription factor 2 (Runx2) Results: Periodontitis reduced PHF8 expression in periodontal tissue, and TAK-242 partially reversed this downregulation. An in vitro experiment revealed that the mRNA and protein expression levels of PHF8 were significantly upregulated during the osteogenic differentiation of PDLCs. Alizarin red staining showed that the mineralized nodules of PDLCs in osteogenic induction group were more than those in control group. Real-time PCR and western blot results indicated that Pg-LPS inhibited PHF8 expression and upregulated TLR4 expression in PDLCs.TAK-242 inhibited TLR4 and partially reversed the inhibition of PHF8 expression and osteogenic differentiation induced by Pg-LPS in PDLCs Conclusion: PHF8 and TLR4 play important roles in periodontitis. Pg-LPS inhibits the expression of PHF8 via upregulation of TLR4 and might further inhibit the osteogenic differentiation of PDLCs. However, the specific mechanisms involved remain to be explored.

DkXTH1 promoted cell elongation and more strength to maintain structural integrity by involving in cell wall assembly, thus enhanced tolerance to abiotic stress with broader phenotype in transgenic plants. Xyloglucan endotransglucosylase/hydrolase (XTH) is thought to play a key role in cell wall modifications by cleaving and re-joining xyloglucan, and participates in the diverse physiological processes. DkXTH1 was found to peak in immature expanding persimmon fruit, and its higher expression level exhibited along with firmer fruit during storage. In the present study, transgenic Arabidopsis and tomato plants were generated with DkXTH1 constitutively expressed. Overexpression of DkXTH1 enhanced tolerance to salt, ABA and drought stresses in transgenic Arabidopsis plants with respect to root and leaf growth, and survival. Transgenic tomatoes collected at the mature green stage, presented delayed fruit softening coupled with postponed color change, a later and lower ethylene peak, and higher firmness in comparison with the wild-type tomatoes during storage. Furthermore, broader leaves and tomato fruit with larger diameter were gained in transgenic Arabidopsis and tomato, respectively. Most importantly, transgenic plants exhibited more large and irregular cells with higher density of cell wall and intercellular spaces, resulting from the overactivity of XET enzymes involving in cell wall assembly. We suggest that DkXTH1 expression resulted in cells with more strength and thickness to maintain structural integrity, and thus enhanced tolerance to abiotic stress and delayed fruit softening in transgenic plants.

Organic acid is an important indicator of fruit quality, and malate is the predominant organic acid in apple fruit. However, the regulation of malate metabolism in postharvest fruit is rarely reported. Here, we found that, compared with a control treatment, a 10 mM γ-aminobutyric acid (GABA) treatment remarkably delayed the loss of tiftratable acidity and malate and increased the succinate and oxalate contents in “Cripps Pink” fruit stored in polyethylene bags at room temperature. The higher malate levels in GABA-treated fruit were accompanied by higher activities of cytosolic nicotinamide adenine dinucleotide-dependent malate dehydrogenase (cyNAD-MDH) and phosphoenolpyruvate carboxylase (PEPC) but lower cytosolic NAD phosphate-dependent malic enzyme (cyNADP-ME) and phosphoenolpyruvate carboxykinase (PEPCK) activities than those seen in control fruit. Notably, ethylene production was significantly reduced by GABA treatment, paralleling the downregulation of MdACS, MdACO, and MdERF expression. Meanwhile, GABA treatment also enhanced the activity of the GABA shunt and promoted the accumulation of GABA. This study provides new insights into the regulation of malate metabolism and reports for the first time the possible interplay between GABA and ethylene signaling pathways in apple fruit during postharvest storage.

BZR transcription factors are critical components of the brassinosteroid signaling pathway, but their possible roles in fruit ripening have rarely been reported. In this study, four BZR sequences were isolated from persimmon fruit. Among the four BZR genes, DkBZR1/2 were expressed in persimmon fruit, and a Western blot assay showed that the protein level of DkBZR1 decreased and that dephosphorylated DkBZR2 protein gradually accumulated during the storage period. DkBZR1/2 protein were localized in both the nucleus and cytoplasm and accumulated in the nucleus after 24-epibrassinolide treatment. DkBZR1 can suppress the transcription of DkEGase1 and DkACS1 by binding to the BRRE motif in their promoters and that DkBZR2 can activate the transcription of DkPL1 and DkACO2 by binding to the E-box motif in their promoters. The transient overexpression of DkBZR2 promoted the conversion of acid-soluble pectin to water-soluble pectin and increased ethylene production in persimmon fruit. Our findings indicate that DkBZR1 and DkBZR2 serve as repressors and activators of persimmon fruit ripening, respectively.